Intercommunicating-telephone system and apparatus.



F'a'cenred Apr. 3, |900 W. D. GHARKY. INTEBCOMMUNICATING TELEPHONE SYSTEM AND APPARATUS.

(no Model.)

(Application med Apr. 1, 189s.)

C) C) ROK@ O ojb@ "om Winedd: uelzlor: 7% MM2. Mm@ M w No. 646,690. Patented Apr. 3, |900.

W. D. GHARKY.

mnancommumcATmG TELEPHQNE SYSTEM Aun APPARATUS..

(Application med Apr. 1, 159s.) (No Model.) 4 Sheets-Sheet 2 FIGC? No. 646,690. Patented Apr. 3, |900. W. D. GHARKY.

INTERCUMMUNICATING TELEPHDNE SYSTEM AND APPARATUS.

(Applieation led Apr. 1, 1898.) (No Model.) 4 Sheets-Sheets,

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Tn: Nonms Ferias co., PHOTO-uno., WASHINGTON. q. r

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w. u. GHABKY. INTERGDIMUNICATING TELEPHONE SYSTEM AND APPARATUS.

v (Appximmn mail. 151868.)

Patented A/pr. 3, 1900.

4 Sheets-Sheet 4.

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f my@ iINrrnn STATES PATENT Critici-3.

IVILLIAM D. GHARKY, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TC TIAIE SUN ELECTRIC MANUFACTURING COMPANY, OF NEIV JERSEY.

iNTERCOiViMUNlCATlNG-TELEPHONE SYSTEM AND APPARATUS..

SPECIFICATION forming pare of Letters Patent No. 646,696, dated April 3, 1900.

Application filed April l, 1898. Serial No. 676,041. (No model.)

To all whom t may concern.-

Be it known that LtVLLAMD, GHARKY, a citizen of the United States of America, residing in the city and county of Philadelphia, in the State of Pennsylvania, have invented certain new and useful Improvements in Intercommunieating-Telephone Systems and Apparatus, of which the following is a true and exact description, referencebeing had to the accompanying drawings, which form a part thereof. i

My invention relates to intercommunicatin g-telephone systems which are known in the Patent Office classification as house systems.77

Myinvention has for its object the production of a systemof this kind and ot' instruments therefor which shall give maximum eflciencyin service, compactness in construction, secrecy in operation, and simplicity of parts.

In order to attain my objects I use the devices hereinafter described in detail and broadly as follows:

Supposing there are a number of stations connected together in accordance with my invention, a cable passes through all the stations, having for its entire length a twisted pair of insulated wires foreach station and an eXtra pair carrying battery-current for calling purposes. At each station a metallic box or casing is provided, containing the entire mechanism required, except the receiver and the local talking-battery--that is, the transmitter, the ind uction-coil, the bell, the switchhook, and a small push-button switchboard. The instrument shown in the accompanying drawings is adapted for use with ten stations and `the outside dimensions are about three by four by eight inches. Compactness is thus fully attained. From each wire in the cable a tap is taken off at each station to an appropriate terminal. At each station are the usual line and local circuits, with connections for the call-bell, the transmitter, and receiver, controlled by a switch-hook in the usual manner. Each substation has two pairs of busbars, constituting part of the little switchboard. One pair of bus-bars is connected to the local circuits and also tothe line-Wires belonging to the particular station. Arranged to cooperate with these bus-bars are push-buttons carrying pairs of contact-springs, each pair corresponding to some other station and being connected to the taps from the wires belonging to that station. From this it is obvious that it is only necessary to operate any given push-button in o rder to connect the wires leading to the corresponding station to the local circuits through the bus-bars. The second pair of bus-bars are connected to the battery-wires in the cable, Thus if any pushbutton is depressed until its springs come in contact with the battery bus-bars obviously battery-current will immediately flow out over the corresponding line to ring the bell at the appropriate station.

Thus far I have described a simple system, using metallic circuits throughout, with induction-coils and local batteries, thus having a very high efficiency; but without the provision of some further device to prevent listening in the system would be open to a grave objection. Such provision I make as follows: Suppose station 3 h-as pushed in button No. 8. No. Ss wires are connected to No. Ss local circuits through his bus-bars and the conversation is over No. Ss metallic circuit. If secrecy is desired, No. 8 also depresses his No. 3 button, thus connecting No. 3s linewires to his bus-bars. also depresses an additional button, which I call the secrecy-switch.7 The effect of this at each station is to connect the local instruments in a bridge from the bus-bars in multiple to the individual line-wires in multiple. A complete circuit is thus formed between the two stations, having each side composed of the pair of wires belonging to one station. Conversation then may proceed without fear of interruption, for if any outsider should connect himself by the appropriate push-button at his station to one of the pairs thus in use he would hear nothing,as he would simply be bridged across two component elements of a single conductor.

Referring to the accompanying drawings, Figure l is a vertical sectional View of the shell or case at one station, with its contained apparatus, taken on the line l l of Fig. 2. Fig. 2 is a rear view of the same. Fig. 3 is a horizontal sectional View on the line 2 2 of Each of the two then I IOO Fig. l. Fig. et is a plan view el' one of the blocks for the push-buttons with its connected apparatus. Fig. 5 is a perspective view of said block. Fig. G is a combination view showing a section of the block on the line t 4; of Fig. et and a diagram of the localstation circuits. Fig. 7 is aperspective View of one push-button of the ordinary type, and Fig. 8 is a section through the secrecy-button. Fig. 9 is a diagram of the circuit of one station, showing its connections to other stations. Figs. l0 and 1l are diagrams of several circuits with their station connections. Figs. 12, 13, 14, and l5 are diagrams illustrating the connections for secrecy. Fig.

1G is a partial diagram of two stations, showing the method of connecting the battery to the calling bus-bars with a turn around the induction-coil.

I shall first describe the mechanical construction of my station apparatus; second, the circuits under various conditions, and, third, the operation of the whole.

Referring to Fig. l, A is a shell or casing of substantially-rectangular shape and of a sufficient depth to accommodate the apparatus to be described. In the face of this casing, which is preferably of metal, I form two openings n and a. In the lowerone, a, I fit a transmitter having a fiange C, which overlies the edge of the opening and which has the usual mouthpiece G. In the upper opening a' I 'fit a block or blocks G and G, of insulating material, secured to the casing, as shown in Fig. 3, by side screws.

Back of the transmitter a vertical panel B, of insulating material, is provided, which serves to support the ind uction-coil I, the terminals of the wires coming` into the instrument (shown at N N2, dsc., in Fig. 2) and the springs L, L', and L2 of the local circuit. In the chamber formed between the panel B and the transmitter thc station call-hell is placed, together with the induction-coil, the former being shown at J in Fig. l and the latter at I.

Journaled within a boss D on the side of the shell A is a spindle D', carrying upon its outer end the hook-lever D2 and upon its inner end an oppositely-extending arm D, thus constituting a lever of the vfirst order. Upon the arm D3 a transverse pin D'l is mounted, which. as it moves up and down with the hooklever makes contact with either the springs L L or the spring L2. In Fig. G the connections of these springs are clearly shown, the spring L2 constituting the terminal of the eircuit l of the circuit-bell .I and the springs L and L constituting the terminals for the primary P4 P and the secondary P2 I. It will be understood that the weight of the receiver (shown in dotted lines at C2 in Figs. 1 and 2) moves the switch-lever in one direction and a spring Q in the other.

By referring to Fig. 2 it will be observed that there is a terminal on the panel B for every wire, and from these terminals, constituting distriln'ltiiig-terminals, short jumperwires are led up to the appropriate connections in the switchboard at the top of the casing. This switchboard consists, essentially, of a series of push-buttons for the purpose of making connections, together with detents controlled by the switch-hook, and serving to retain the buttons depressed as long as the receiver is off the hook.

In Fig. 5, G is a block of insulating material having depressions Gl1 and G5, rearwardlyextending projections G, and perforations G in alinement with the depressions Gl. Each push button has a spindle II, extending through one of the perf orations GS, and a head II. NVithin the block the perforations G are` enlarged, as at G2, to a diameter sufficient to receive the head II and a spring Ilz, which tends to keep the head projected forward. At the rear of the block G each spindle Il' carries a cross-head IIB, which is adapted to work back and forth between two of the projections GG and which carries parallel contact;- springs If and L, which extend forward on opposite sides of the block and lie within the depressions G4. Each cross-head carries a pin h2, which when the push-button has been dcpressed engages with a hooked detent lt la, the. These detents are in the form of small hooked pawls, carried upon and rigid with transverse pivoted shafts E E0. The pawls are all connected and controlled through a pivoted lever E, having arms E and E2, the arm E being connected to the switch-arm D by a link D, whose lower end is slotted at d" to receive a pin D, sufficient lost motion being thus provided to allow a push-button to lift a pawl and becaught without moving the switclrhook.

Lying within the depressions Gfof the block G and overlying all ol.' the springs LSL, itc., are bus-bars M M' M2M. Two of these busbars M and lll are terminals of a calling battery-circuit. The other two, M2 and Mf, are terminals of the local-station circuits. It will be observed upon reference to Fig. l. that when a push-button II is depressed the springs L5 LU will first come into contact with the bars M" M3 and at the same instant will be latched. The effect of this is to connect the line-wires leading to the .springs to the bus-bars and through them to the local circuits. It' the but-ton be further depressed, the springs will leave the bars lll." M3 and come into contact with the second pair, M M, connected to the battery circuit, thus connecting the linewires to battery.

Lying in rear of the blocks G G are insulating-blocks F F', upon which are secured springs LS L, the., which extend forwardly and rest upon the push-button springs. These springs LJ L4, ttc., being directly connected by the jumper-wir es to the terminals on the distributing-board, as clearly shown in Fig. 2, serve to connect the individual line-circuits each to its proper pair of push-button springs L5 L Moreover, a sliding contact is provided between the springs which is kept rrVI igt

back to battery.

clean by the movements of the respective buttons.

The secrecy-switch is shown as to its mechanism in Figs. 4 and 8. It consists of a pushbutton in every respect similar to the rest of the set. Itwill be observed that taking out this secrecy push-button there are only nine buttons left for the ten lines. This is, however, all that is necessary, because at each station it is only the other stations that are represented by buttons, the local and outgoing home line-circuits being connected to the busbars M2 M3. In Fig. 4 it will be observed that the ends of the bus-bars M M2 are separate insulated portions m m2. Beneath the block G the other pair of bus-bars have similar insulated end portions. In Fig. 8 it will be observed that the push-button` springs l5 l. are somewhat shorter than the corresponding springs of theother buttons and normally rest upon the short insulated ends m2 m2 of the bus-bars. When the push-button 7L is depressed and retained by the detent c4, these springs will pass into contact with the short insulated pieces m m. The springs Z3 Z4 are the terminal springs for this button.

Turning nowto the circuit connections,Fig. 9 shows the circuit of one station extending to two other stations. The conductors N N' are bridged by the telephone set through the hook D3 andpass through the cable in a twisted condition, as indicated at n. At each of the other stations multiple taps from the conductors N Nl are connected to the contacts LGL5,\vliich are the springs of the individual push-buttons belonging to the circuit at those stations.

Fig. l0 shows two stations, one of which is calling the other. The station at theleft has conductors N2 N2, bridged by its telephone set and extending to the push-button springs LGL5 at the other station. The station at the right, which is being called, has its hook down and the bell J bridged across its line-wires N N,lwhich extend to push-button springs at the left-hand station. The battery K is connected through conductors O O to the proper bus-bars INI M at both stations. Supposing that the left-hand station in this figure is calling the rightn hand station, he has depressed the proper button until the springs Lland L5 come into contact with the bus-bars M M', when current will immediately pass from battery K to bar M, to spring L6, to conductor N, to bell J, to contact L2, to hook D2 by conductor N', to spring L5, to bar. M', and Before the calling-station has produced this condition, however, he rst partially depresses the push-button H to connect the springs L6 L5 with the bus-bars M2 and M2, whereby he was enabled to listen in across the wires N N' to determine whether the other station was busy. Fig. Il shows more clearly the conditions which permit this. In this figure it will be observed that each station has its telephone C2 connected across the bus-bars to which its line-wires are joined.

Now suppose that the two right-hand stations are conversing over the conductors N N belonging to one of them. Suppose the extreme left-hand station desires to converse with the eXtreme right-hand. The springs L( L5 are first pushed into contact with the bus-bars M2 M3, which obviously bridges telephone C2 across the conductors N N'. The conversation going on can then be heard, showing the lines to be busy. Suppose, however, that the left-hand station had desired to converse with station No. 3. He connects conductors N2 Ns by the appropriate push-button to his busbars, when again he will be placed, through the bus-bars at the other station, in shunt of the connected telephones on circuit N N.

Referring now to the connections of the secrecy-switch, Fig. 14 shows in its vsimplest form the circuit between a calling and a called station when the secrecy-button has been depressed. In this iigure,'N N are the line conductors belonging to one station and terminating in its bus-bars, and N2 N3 are those of the other station.` It will be observed that the telephones C2 are so connected as to utilize each of the pairs in parallel as a single conductor. Now if any other station should attempt to connect springs L6 L5 to its bus-bars, thereby bridging its telephone across the pair N N or N2 N2, nothing would be heard, for the reason that each of these pairs is but a single conductor in the secret circuit and both of its constituent wires are always at the same potential. In order that the calling-station may be apprised of the condition of affairs, I adopt the busy test. (Shown in Fig. 16.) The battery-wire O before being connected to the bus-bar M is given a few turns about the induction-coil I. Now if a substation operator should connect springs L5 Li to the bus-bars M Mvfor the purpose 0f calling and a dead short circuit should be in existence on the individual pair, as shown in Fig. I4, there would be a sudden rush of current from the battery through the wires O O and the branch around the induction-coil, which would produce a loud click in the local receiver, thus announcing cline is busy.7 Moreover, this induction-coil connection is useful in ordinary calling, as the making and breaking of the circuit by the vibratin g bell at the distant station causesahumming or buzzing noise in the receiver, which announces that the call is being received. This operation depends entirely upon the capacity of the lines and cables and not upon the continuity of the receiver-circuit. The sudden rush of current in the case of a short circuit by the secrecy-switches or the rapid makes and breaks when the distant bell is in circuit cause the charging of the receiver-circuit, even though one end of it be open, sufficiently to produce the noises referred to.

Referring now to Fig. 15, it should be observed that the line-wires N and N are connccted through the short insulated pieces m and m2 to the bus-bars M2 M2, the telephones IIO f1. stacco C' C2 and the bell J being alternately bridged through the action ol:- the switch-hook D3. XVhen the secrecy-switch is depressed, however, the circuit from m2 is adapted to be broken, as shown in dotted lines at Z1 and connected to m, while the circuit from busbar M2 is adapted in the same way to be connected at Z3 to the bus-bar Mii. The actual details ol' the connections are more clearly shown in Figs. l2 and 13, the former giving the conditions before and the latter after the secrecy-switch has been pushed in. In Fig. l2, it will be observed, the wire N is connected with both contacts m and m3 and also with the telephone C2. Conductor N is connected direct to the spring ZG, normally resting in contact with the contact m2, connected to the bus-bar M2. The spring Z5, normally resting in contact with the terminal m3, is connected with the-bus-bar M3. It will thus be apparent that with the receiver oft the hook the telephone set is bridged across the two conductors N N and will be in metallic circuit with any one who at another station may connect those conductors to his busbars or With any other line whose springs L Il may be connected with the home busbars. In Fig. 13 the conditions are shown which exist at each station after the secrecyswitch ZL has been pushed in. The spring Zi has left the contact-terminal m2, thereby being disconnected from the bus-bar M2, and is in contact with the terminal m, thus crossing the conductors N N together and joining them both through the branch from N to the telephone C2. The spring Z5 has left the contact ma, thereby disconnecting` conductor N from the bus-bar M3, and has completed the connection from the latter to the Contact 771/. A circuit may now be traced from conductors N N in parallel through the branch 'from N to the telephone C2, through the inductioncoil I, and the switch-hook D3 in one direction to the bus-bar M2 direct and inthe other through the contact m/ and the spring Z5 to the bus-bar M3, the bus-bars thus being in parallel, thence, as shown, to springs L5 L6 in parallel and out to the other station whose button is depressed, where the conditions are supposed to be identical with those here described. The circuit shown in Fig. lat is thus established.

Although I have described speci tie devices and have used specific terms for the sake of clearness, I wish it to be distinctly understood that I do not consider my invention as limited to the specific forms of apparatus or the specific circuit connections shown. I believe I am the first to employ metallic circuits in the manner described and ior the purpose indicated.

. Iaving now described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In anintercomm unicati11g-telephone system having a series of stations, a metallic eircuit `tor each station said circuit connecting with each other station, a battery and a metallic circuit l'rom the battery, connected with each station; a pair or pairs of terminals, as M M', in each station connected with the battery-circuit, in combination with a series of pairs of terminals, as I!E L, one pair connected in each station with each other station-circuit, a pair or pairs of terminals, as M2 M3, in each station each connected with the talking and ringing circuit of the home station, and with the circuitleading from the home station to each other station, spring-aetuated switching mechanism normally held to severconnection between the terminals aforesaid but adapted to couple the terminals M M/ and L'1 L3 and, alternatively, the terminals M2 M3 and L" L3 as specilied and so as to connect the selected station-circuit alternately with battery and with the home talking-eircuit, catches arranged to hold the switches in position to maintain the latter connection, and a common switch-releasing device whereby all switches of the series will be returned to normal position.

2. In anintereommunicatiug-telephonesystem having a series ol. stations and metallic circuits ior each station connecting with all the other stations of the series, the combination at each station of a local primary-circuit and secondary-circuit connection, said secondary-circuit connection normally connecting in series with the metallic circuit peculiar toits station, means for coupling in series the said metallic circuit with each el' the metallic circuits peculiar to the other stations, and means as described at each station whereby two coupled stations can shift the local secondary-circuit connection onto the metallic circuit-wires peculiar to the station joined in parallel as one wire, and connect these doubled metallic circuits in series atboth coupled stations through the said local secondary-ci r cuit connections, whereby listening in from a third station is prevented.

In an intercommunicating-telephone system having a series of stations and metallic circuits for each station connecting with all the other stations of the series, the combination at each station ot a local primary-circuit and secondary-circuit connection, said sccondary-circuit connection normally connecting inseries with the metallic circuit peculiar to its station, means Vfor coupling in series the said metallic circuit with each oi' the metallic circuits peculiar to the other stations, means as described at each station whereby two coupled stations can shift the local secondarycircuit connection onto the metallic circuitwires peculiar to the station joined in paral` lel as one wire and connect these doubled metallic circuits in series at both coupled stations through the said local secomlary-circuit connections, a ringing battery or batteries, a metallic circuit or circuits leading therefrom and connected with terminals in each station,

said battery circuit or circuits making several turns around the induction-coil of the stations local circuit, and means at each station for connecting said battery-terminals in series with the terminals of the metallic cir-- cuits ot' the other stations, all substantially as described, and so that listening in can be prevented but a signal given to the calling station of the condition of the called circuit.

4. ln an intercommunicating-telephone callbox, one or more terminals connected to a ringing-circuit, and one or more terminals connected With the local circuit and With the line Wire or Wires peculiar to the box, in combination With a series of terminals connected one with each line Wire or Wires of connected stations and arranged When moved relatively to the other terminals to alternatively connect these Wires with a local-circuit terminal and with a ringing-circuit terminal, springs to return said movable terminals to non-contacting position, and latches to hold them in position of contact with the local-circuit terminals, only.

5. In an intercom municating-telephone callhox; one or more terminals connected to a ringing-circuit,and one or more terminals connected with the local circuit and with the line Wire or wires peculiar to the boX, in combination with a series of terminals connected one with each line Wire or Wires of connected stations and arranged when moved relatively to the other terminals to alternately connect t-hese Wires with a local-circuit terminal and With a ringing-circuit terminal, springs to return said movable terminals to non-contacting posit-ion, latches to hold them in position of. contact with the localcircuit terminals, and latch-releasing mechanism acting on all latches at once to insure return of all movable terminals to non-contacting position.

G. Inanintercommunicating-telephonebox the combination, with bus-bars, as M and M2, connecting respectively with a battery-circuit and with the local telephone-circuit,of a series of sliding springs, as L, each connecting With a line-Wire leading to the box, a push-button,

' as H, connected to the spring, return-springs,

as lli, and latches, as E4, arranged to hold the sliding springs in contact With the bus M2, all substantially as specified.

7. Inanintercommunicating-telephonebox the combination With the bus-bars, as M and M2, connecting respectively with a riiigingcircuit and with the local telephone-circuit, oi a series of sliding springs, as L, each connecting With a line-wire leading to the box, a push-button, as H, connected to each spring, return-springs, as H3, latches, as E4, arranged to hold the sliding springs in contact with the bus M2 and latch-releasing mechanism controlled by the position of the telephone-hook, all substantially as specified.

8. In an intercommunicating-telephone box having provision for metallic circuits connecting it With similar-boXes,the combination with terminals, as M2 M3, normally connected in series with the Wires forming the metallic circuit peculiar to the box, means for coupling the circuit-Wires in parallel as one Wire, a local telephone-circuit normally bridged across and in series With the line-Wires but arranged when said Wires are coupled in parallel as one Wire to be connected from them to both terminals-M2 M3 in parallel as one and means for coupling said terminals With the line-Wires of other stations, substantially as specified.

9. An intercommunicating-telephone-box casing having an opening a in its face anda transmitter inserted therein, a second opening c and blocks as G and G inserted therein, push-buttons, and stems therefor, carrying contacts, Working in said blocks, and busbars for local circuits supported on theblocks in proximity to said contacts.

10. In combination With an intercommunieating telephone, line-terminal springs having forwardly-extending arms as L4,with moving spring-switches as L6 with which the said arms of the terminal springs maintain constant sliding contact, one or more bus-bar terminals as M M2,With which the moving switchsprings are adapted to come in contact, and means to maintain them in such contact.

XVM. D. GHARKY.

NVitnesses:

CHAS. F. MYERs, D. STEWART. 

